1. Field of the Invention
The present invention relates to a rotary drum with points of a new type, the points being for use on textile machines, such as openers, tearers or disintegrators.
2. Description of the Relevant Art
It is known that such a textile machine includes one or many successive drums, upon which are passed textile materials. This is done for the purpose of opening virgin fibers, or for reproducing fibers by putting together scraps.
For treating these fibers and scraps, the known machines include one or more successive drums, as a function of the desired degree of refining. These drums are generally equipped with points or needles, with round or oblong section, mounted in supports of wood, metal or plastic material called "staves." Each stave includes therefore a plate more or less curved, on the exterior of which the points or teeth of the drum pass. These staves are mounted on the periphery of a cylinder or rotor: the entirety constitutes the drum.
The attaching of the staves on the cylinder of a drum of the known type is done in a conventional manner, such as with screws and nuts. To attach the staves in this manner, one engages each screw through the stave, then through a perforation situated opposite the cylinder, where it enters from the exterior toward the interior. The head of the screw takes support on the plate of the stave. The threaded shaft of the screw passes in this way to the interior of the cylinder, where one then puts in place a tightening nut. Consequently, one must provide openings of large enough dimensions, in the supporting end plates situated at two extremities of the cylinder, in order to permit the operator to pass his arm through these openings to reach the internal face of the cylinder, where each nut is put in place.
This structure of the drums of the known type is limited by the following inconveniences. Access to the internal face of the cylinder is difficult, because the diameter of the cylinder is smaller. On the other hand, the axial length of the cylinder is limited, by the length of the arm of the operator. In practice, the length of the drum cannot pass 11/2 meters and its diameter must remain above 3/4 meter. In addition, labor time is too large for changing or replacing the staves: the nuts must be introduced, put in place and tightened one by one in the interior of the cylinder.
By way of example, a tearing drum of a diameter of one meter and of a length of one meter requires generally 340 screws of attachment for the staves. These staves constitute parts of wear that it is necessary to change, for example, every 800 hours of operation. This frequency of change is yet augmented if the textile scraps for tearing are susceptible to containing foreign bodies which deteriorate the point of the drum.
To try to avoid these inconveniences, the holes of attachment pierced in the cylinder could be threaded: that would permit screwing the screws from the exterior in each machined threading in the thickness of the cylinder. In practice, such a solution is unusable, because on the one hand, that would require the face of the cylinder to have an exaggerated thickness, while on the other hand, the deterioration of a single thread would result in the destruction of the cylinder. It is not possible to take such a risk for operations of installing and removing staves, which are continually repeated operations on a given drum.